Certain divisible hypergroups. Pianskool, Sajee; Wasanwichit, Amorn; Kemprasit, Yupaporn — 2005 General Mathematics
Cauchy's functional equation in restricted complex domains. Pimsert, Watcharapon; Laohakosol, Vichian; Pianskool, Sajee — 2006 International Journal of Mathematics and Mathematical Sciences